Last Updated: 2007-11-23 10:32:33 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Free fatty acids empty from the stomach more slowly and suppress appetite more potently than triacylglycerides, results of a study suggest. Free fatty acids also stimulate the gastrointestinal hormones cholecystokinin (CCK) and peptide-YY (PYY), which are known to send satiety signals. These findings could have application in obesity treatment.

Researchers studied nine healthy normal-weight men on three separate occasions, to determine the effects on gastric emptying, gut hormones, and appetite of 40 grams of the free fatty acid (FFA) oleic acid, 40 grams of the triacylglyceride (TG) macadamia oil, and 600 mL 4% milk protein (control) administered intragastrically

Dr. Tanya J. Little, from the University of Adelaide, South Australia, and colleagues report in the November issue of Gastroenterology that gastric emptying of FFA was "much slower than that of TG (p < 0.05), with greater retention of FFA, than TG, in the proximal stomach (p < 0.001)."

Hunger was less (p < 0.05), and fullness was greater (p < 0.05), after FFA when compared with control and TG, and energy intake tended to be less.

FFA also produced an earlier and more dramatic increase in plasma CCK and PYY levels, relative to TG and control. "The clinical potential of this finding is considerable," write the authors of an accompanying editorial, as CCK and PYY "are regarded as major players in induction of satiation."

"Greater understanding of the neurohormonal control and the gastric emptying and uptake of fat moieties may lead to novel applications for obesity management," note Drs. Michael Camilleri and Seth Sweetser of the Mayo Clinic College of Medicine, Rochester, Minnesota.

Gastroenterology 2007;133:1124-1131,1367-1369.